Molecular and clinical characterization of human respiratory syncytial virus in South Korea between 2009 and 2014.

Respiratory syncytial virus (RSV) can cause serious respiratory infections, second only to influenza virus. In order to know RSV's genetic changes we examined 4028 respiratory specimens from local hospital outpatients in Gyeonggi Province, South Korea over six consecutive years by real-time one-step RT-PCR; 183 patients were positive for RSV infection. To investigate the specific distribution of RSV genotypes, we performed partial sequencing of the glycoprotein gene. Of the 131 RSV-A specimens sequenced, 61 (43·3%) belonged to the ON1 genotype, 66 (46·8%) were NA1 genotype, 3 (2·1%) were GA5 genotype, and 1 (0·7%) belonged to the GA1 genotype. Of the 31 RSV-B specimens sequenced, 29 were BA9 genotype (87·9%) and 2 were BA10 genotype (6·1%). The most common clinical symptoms were fever, cough, nasal discharge, and phlegm; multiple logistic regression analysis showed that RSV-positive infection on pediatric patients was strongly associated with cough (OR = 2·8, 95% CI 1·6-5·1) and wheezing (OR = 2·8, 95% CI 1·7-4·4). The ON1 genotype was significantly associated with phlegm (OR = 11·8, 95% CI 3·8-46·7), while the NA1 genotype was associated with the pediatric patients' gender (males, OR = 2·4, 95% CI 1·1-5·4) and presence of chills (OR = 5·1, 95% CI 1·1-27·2). RSV subgroup B was showed association with nasal obstruction (OR = 4·6, 95% CI 1·2-20·0). The majority of respiratory virus coinfections with RSV were human rhinovirus (47·2%). This study contributes to our understanding of the molecular epidemiological characteristics of RSV, which promotes the potential for improving RSV vaccines.